The lower esophageal sphincter (LES) is prone to relaxing intermittently. As a consequence, fluid from the stomach can pass into the esophagus since the mechanical barrier is temporarily lost at such times, an event hereinafter referred to as “reflux”.
Gastroesophageal reflux disease (GERD) is the most prevalent upper gastrointestinal tract disease. Current pharmacotherapy aims at reducing gastric acid secretion, or at neutralizing acid in the esophagus. The major mechanism behind reflux has been considered to depend on a hypotonic lower esophageal sphincter. However, recent research (e.g. Holloway & Dent (1990) Gastroenterol. Clin. N. Amer. 19, pp. 517-535) has shown that most reflux episodes occur during transient lower esophageal sphincter relaxations (TLESR), i.e. relaxations not triggered by swallows. It has also been shown that gastric acid secretion usually is normal in patients with GERD.
Consequently, there is a need for a therapy that reduces the incidence of TLESR and thereby prevents reflux.
GABAB-receptor agonists have been shown to inhibit TLESR, which is disclosed in WO 98/11885 A1.
GABAB Receptor Agonists
GABA (4-aminobutanoic acid) is an endogenous neurotransmitter in the central and peripheral nervous systems. Receptors for GABA have traditionally been divided into GABAA and GABAB receptor subtypes. GABAB receptors belong to the superfamily of G-protein coupled receptors (GPCRs).
The most studied GABAB receptor agonist baclofen (4-amino-3-(p-chlorophenyl)butanoic acid; disclosed in CH 449046) is useful as an antispastic agent. EP 356128 A2 describes the use of the GABAB receptor agonist (3-aminopropyl)methylphosphinic acid for use in therapy, in particular in the treatment of central nervous system disorders.
EP 463969 A1 and FR 2722192 A1 disclose 4-aminobutanoic acid derivatives having different heterocyclic substituents at the 3-carbon of the butyl chain. EP 181833 A1 discloses substituted 3-aminopropylphosphonic acids having high affinities towards GABAB receptor sites. EP 399949 A1 discloses derivatives of (3-aminopropyl)methylphosphinic acid, which are described as potent GABAB receptor agonists. Still other (3-aminopropyl)methylphosphinic acids and (3-aminopropyl)phosphinic acids have been disclosed in WO 01/41743 A1 and WO 01/42252 A1, respectively. Structure-activity relationships of several phosphinic acid analogues with respect to their affinities to the GABAB receptor are discussed in J. Med. Chem. (1995), 38, 3297-3312. Sulphinic acid analogues and their GABAB receptor activities are described in Bioorg. & Med. Chem. Lett. (1998), 8, 3059-3064. For a more general review on GABAB ligands, see Curr. Med. Chem.-Central Nervous System Agents (2001), 1, 27-42.
Positive Allosteric Modulation of GABAB Receptors
2,6-Di-tert-butyl-4-(3-hydroxy-2,2-dimethylpropyl)phenol (CGP7930) and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-2,2-dimethylpropanal (disclosed in U.S. Pat. No. 5,304,685) have been described to exert positive allosteric modulation of native and recombinant GABAB receptor activity (Society for Neuroscience, 30th Annual Meeting, New Orleans, La., Nov. 4-9, 2000: Positive Allosteric Modulation of Native and Recombinant GABAB Receptor Activity, S. Urwyler et al.; Molecular Pharmacol. (2001), 60, 963-971).
N,N-Dicyclopentyl-2-methylsulfanyl-5-nitro-pyrimidine-4,6-diamine has been described to exert positive allosteric modulation of the GABAB receptor (The Journal of Pharmacology and Experimental Therapeutics, 307 (2003), 322-330).
For a recent review on allosteric modulation of GPCRs, see: Expert Opin. Ther. Patents (2001), 11, 1889-1904.
Outline of the Invention
The present invention relates to a compound of the general formula (I)
wherein    R1 represents C1-C10 alkyl; C2-C10 alkenyl; C2-C10 alkynyl; or C3-C10 cycloalkyl, each optionally substituted by one or more of C1-C10 alkoxy, C3-C10 cycloalkyl, C1-C10 thioalkoxy, SO3R7, halogen(s), hydroxy, mercapto, carboxylic acid, CONR5R9, NR5COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups; or    R1 represents aryl or heteroaryl, each optionally substituted by one or more of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C1-C10C alkoxy, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, nitro, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups, wherein any aryl or heteroaryl group used in defining R1 may be further substituted by one or more of halogen(s), C1-C10 alkyl, C1-C10 alkoxy or C1-C10 thioalkoxy, wherein said C1-C10 alkyl may be further substituted by one or two aryl or heteroaryl groups;    R2 represents C1-C6 alkyl, C1-C6 alkoxy or NR5R6; optionally substituted by one or more of C1-C10 alkoxy, C3-C10 cycloalkyl, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups;    R3 represents C1-C10 alkoxy, optionally substituted by one or more of C1-C10 thioalkoxy, C3-C10 cycloalkyl, keto, halogen(s), hydroxy, mercapto, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups;    C1-C10 alkyl; C2-C10 alkenyl; C2-C10 alkynyl; or C3-C10 cycloalkyl, each optionally substituted by one or more of C1-C10 alkoxy, C1-C10 thioalkoxy, C3-C10 cycloalkyl, keto, halogen(s), hydroxy, mercapto, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups; or    R3 represents aryl or heteroaryl, each optionally substituted by one or more of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C3-C10 alkoxy, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, nitro, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups; or    R3 represents amino, optionally mono- or disubstituted with C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl or C3-C10 cycloalkyl;    Y represents
    R4 represents C1-C10 alkyl; C2-C10 alkenyl; C2-C10 alkynyl; C1-C10 alkoxy; or C3-C10 cycloalkyl, each optionally substituted by one or more of C1-C10 alkoxy, C3-C10 cycloalkyl, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, keto, carboxylic acid, CONR8R9, NR8COR9, CO2R10, COR10, nitrile, SO2NR8R9, SO2R11, NR8SO2R9, NR8C═ONR9 or one or two aryl or heteroaryl groups; or    R4 represents aryl or heteroaryl, each optionally substituted by one or more of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, nitro, carboxylic acid, CONR5R9, NR8COR9, CO2R10, SO3R7, nitrile or one or two aryl or heteroaryl groups, wherein said aryl or heteroaryl group used in defining R4 may be further substituted by one or more of halogen(s), C1-C10 alkyl, C1-C10 alkoxy or C1-C10 thioalkoxy, wherein said C1-C10 alkyl may be further substituted by one or two aryl or heteroaryl groups;    R5 represents hydrogen, C1-C10 alkyl; C2-C10 alkenyl; C2-C10 alkynyl; or C3-C10 cycloalkyl, each optionally substituted by one or more of C1-C10 alkoxy, C3-C10 cycloalkyl, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, carboxylic acid, CONR5R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups;    R5 represents aryl or heteroaryl, each optionally substituted by one or more of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, nitro, carboxylic acid, CONR5R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups;    R6 represents hydrogen, C1-C10 alkyl; C2-C10 alkenyl; C2-C10 alkynyl; or C3-C10 cycloalkyl, each optionally substituted by one or more of C1-C10 alkoxy, C3-C10 cycloalkyl, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups;    R6 represents aryl or heteroaryl, each optionally substituted by C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C1 thioalkoxy, halogen(s), hydroxy, mercapto, nitro, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups;    or R5 and R6 together form a ring consisting of from 3 to 7 atoms selected from C, N and O, wherein said ring is optionally substituted by one or more of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, nitro, keto, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups;    R7 each and independently represents C1-C10 alkyl;    R8 each and independently represents hydrogen, C1-C10 alkyl, aryl or heteroaryl, wherein said aryl or heteroaryl may optionally be further substituted by one or more of halogen(s), C1-C10 alkyl, C1-C10 alkoxy or C1-C10 thioalkoxy;    R9 each and independently represents hydrogen, C1-C10 alkyl, aryl or heteroaryl, wherein said aryl or heteroaryl may optionally be further substituted by one or more of halogen(s), C1-C10 alkyl, C1-C10 alkoxy or C1-C10 thioalkoxy;    R10 each and independently represents C1-C10 alkyl, optionally substituted by aryl or heteroaryl, wherein said aryl or heteroaryl may optionally be further substituted by one or more of halogen(s), C1-C10 alkyl, C1-C10 alkoxy or C1-C10 thioalkoxy;    R11 represents C1-C10 alkyl, aryl or heteroaryl, wherein said aryl or heteroaryl may optionally be further substituted by one or more of halogen(s), C1-C10 alkyl, C1-C10 alkoxy or C1-C10 thioalkoxy;    wherein each of alkyl, alkenyl, alkynyl and cycloalkyl used in defining R1 and R3-R11 may independently have one or more carbon atom(s) substituted for O, N or S; wherein none of the O, N or S is in a position adjacent to any other O, N or S;    wherein each of alkyl, alkenyl, alkynyl, alkoxy and cycloalkyl may independently have one or more carbon atom(s) substituted by fluoro;    with the proviso that R2 may only represent alkoxy if Y represents NHSO2 or NHCS;    as well as pharmaceutically and pharmacologically acceptable salts thereof, and enantiomers of the compound of formula (I) and salts thereof.
According to one embodiment of the present invention R1 represents C1-C4 alkyl, optionally substituted by one aryl or two heteroaryl groups.
According to another embodiment of the present invention, R1 represents aryl, optionally substituted by one or more of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkoxy, SO3R7, halogen(s), hydroxy, mercapto, nitro, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrite or one or two aryl or heteroaryl groups.
In another embodiment of the present invention, R1 represents unsubstituted phenyl.
In yet another embodiment of the present invention, R2 represents C1-C4 alkyl.
In a further embodiment of the present invention, R3 represents C1-C4 alkoxy, optionally substituted by one or more of C1-C10 thioalkoxy, C3-C10 cycloalkyl, keto, halogen(s), hydroxy, mercapto, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrite or one or two aryl or heteroaryl groups.
In another embodiment of the present invention, R3 represents C1-C10 alkyl, optionally substituted by one or more of C1-C10 thioalkoxy, C3-C10 cycloalkyl, keto, halogen(s), hydroxy, mercapto, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrite or one or two aryl or heteroaryl groups.
In a further embodiment of the present invention R4 represents C1-C7 alkyl, C2-C7 alkenyl, C2-C7 alkynyl or C3-C7 cycloalkyl, optionally substituted by one or more of C1-C10 alkoxy, C3-C10 cycloalkyl, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrite, SO2NR8R9, NR8SO2R9, NR8C═ONR9 or one or two aryl or heteroaryl groups, wherein any aryl or heteroaryl group used in defining R4 may be further substituted by one or more of halogen(s), C1-C10 alkyl, C1-C10 alkoxy or C1-C10 thioalkoxy, wherein said C1-C10 alkyl may be further substituted by one or two aryl or heteroaryl groups.
According to a further embodiment of the present invention, R4 represents C1-C4 alkyl, optionally substituted by one or two aryl or heteroaryl groups.
According to another embodiment of the present invention, R4 represents C1-C4 alkyl, substituted by one or two aryl or heteroaryl groups.
In a further embodiment of the present invention, R4 represents aryl or heteroaryl, optionally substituted by one or more of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 thioalkoxy, halogen(s), hydroxy, mercapto, nitro, carboxylic acid, CONR8R9, NR8COR9, CO2R10, nitrile or one or two aryl or heteroaryl groups.
In yet another embodiment of the present invention, R5 represents C1-4 alkyl.
In one embodiment of the present invention, R5 represents methyl.
In yet another embodiment of the present invention, R6 represents C1-4 alkyl.
In a further embodiment of the present invention, R6 represents methyl.
According to another embodiment of the present invention R5 and R6 form a ring consisting of 5 or 6 atoms selected from C, O and N.
In one embodiment of the present invention Y represents

In another embodiment of the present invention, Y represents

According to another embodiment of the present invention,    R1 represents aryl;    R2 represents NR5R6;    R3 represents C1-C10 alkoxy;    Y represents
    R4 represents C1-C10 alkyl; optionally substituted by one aryl; or    R4 represents aryl or heteroaryl, each optionally substituted by one halogen;    R5 represents hydrogen or C1-C10 alkyl;    R6 represents hydrogen or C1-C10 alkyl;    or R5 and R6 together form a ring consisting of from 3 to 7 atoms selected from C or N;    wherein the alkyl used in defining R4 may have one carbon atom substituted for O.
According to yet another embodiment of the present invention,    R1 represents aryl;    R2 represents NR5R6;    R3 represents C1-C4 alkoxy;    Y represents
    R4 represents C1-C10 alkyl; optionally substituted by one aryl; or    R4 represents aryl or heteroaryl, each optionally substituted by one halogen;    R5 represents C1-C4 alkyl;    R6 represents hydrogen, C1-C4 alkyl;    or R5 and R6 together form a ring consisting of from 5 to 6 atoms selected from C or N;    wherein the alkyl used in defining R4 may have one carbon atom substituted for O.
The present invention also relates to a compound selected from    tert-butyl 4-{[(4-chlorophenyl)carbonothioyl]amino}-2-(dimethylamino)-1-phenyl-1H-imidazole-5-carboxylate;    tert-butyl 4-{[(1Z)-(4-chlorophenyl)(pyrrolidin-1-yl)methylene]amino}-2-(dimethylamino)-1-phenyl-1H-imidazole-5-carboxylate;    tert-butyl 4-[(2,3-dihydro-1,4-benzodioxin-2-ylcarbonothioyl)amino]-2-(dimethylamino)-1-phenyl-1H-imidazole-5-carboxylate; and    tert-butyl 4-{[2-(benzyloxy)ethanethioyl]amino}-2-(dimethylamino)-1-phenyl-1H-imidazole-5-carboxylate.
The compounds of formula (I) above are useful as positive allosteric GABAB receptor modulators as well as agonists.
The molecular weight of compounds of formula (I) above is generally within the range of from 300 g/mol to 700 g/mol.
It is to be understood that the present invention also relates to any and all tautomeric forms of the compounds of formula (I).
The general terms used in the definition of formula (I) have the following meanings:    C1-C10 alkyl is a straight or branched alkyl group, having from 1 to 10 carbon atoms, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, isopentyl, hexyl or heptyl. The alkyl groups may contain one or more heteroatoms selected from O, N and S, i.e. one or more of the carbon atoms may be substituted for such a heteroatom. Examples of such groups are methyl-ethylether, methyl-ethylamine and methyl-thiomethyl. The alkyl group may form part of a ring. One or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom.
C1-C4 alkyl is a straight or branched alkyl group, having from 1 to 4 carbon atoms, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, secondary butyl, tertiary butyl. The alkyl groups may contain one or more heteroatoms selected from O, N and S, i.e. one or more of the carbon atoms may be substituted for such a heteroatom. Examples of such groups are methyl-ethylether, methyl-ethylamine and methyl-thiomethyl. One or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom.
C2-C10 alkenyl is a straight or branched alkenyl group, having 2 to 10 carbon atoms, for example vinyl, isopropenyl and 1-butenyl. The alkenyl groups may contain one or more heteroatoms selected from O, N and S, i.e. one or more of the carbon atoms may be substituted for such a heteroatom. One or more of the hydrogen atoms of the alkenyl group may be substituted for a fluorine atom.
C2-C10 alkynyl is a straight or branched alkynyl group, having 2 to 10 carbon atoms, for example ethynyl, 2-propynyl and but-2-ynyl. The alkynyl groups may contain one or more heteroatoms selected from O, N and S, i.e. one or more of the carbon atoms may be substituted for such a heteroatom. One or more of the hydrogen atoms of the alkynyl group may be substituted for a fluorine atom.
C3-C10 cycloalkyl is a cyclic alkyl, having 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl. The cycloalkyl may also be unsaturated. The cycloalkyl groups may have one or more heteroatoms selected from O, N and S, i.e. one or more of the carbon atoms may be substituted for such a heteroatom. One or more of the hydrogen atoms of the cycloalkyl group may be substituted for a fluorine atom.
C1-C10 alkoxy is an alkoxy group having 1 to 10 carbon atoms, for example methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, secondary butoxy, tertiary butoxy, pentoxy, hexoxy or a heptoxy group. The alkoxy may be cyclic, partially unsaturated or unsaturated, such as in propenoxy or cyclopentoxy. The alkoxy may be aromatic, such as in benzyloxy or phenoxy.
C1-C4 alkoxy is an alkoxy group having 1 to 4 carbon atoms, for example methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, secondary butoxy, tertiary butoxy. The alkoxy may be cyclic, partially unsaturated or unsaturated, such as in propenoxy or cyclopentoxy.
C1-C10 thioalkoxy is a thioalkoxy group having 1 to 10 carbon atoms, for example thiomethoxy, thioethoxy, n-thiopropoxy, n-thiobutoxy, thioisopropoxy, thioisobutoxy, secondary thiobutoxy, tertiary thiobutoxy, thiopentoxy, thiohexoxy or thioheptoxy group. The thioalkoxy may be unsaturated, such as in thiopropenoxy or aromatic, such as in thiobenzyloxy or thiophenoxy.
The term “aryl” is herein defined as an aromatic ring having from 6 to 14 carbon atoms including both single rings and polycyclic compounds, such as phenyl, benzyl or naphtyl. Polycyclic rings are saturated, partially unsaturated or saturated.
The term “heteroaryl” is herein defined as an aromatic ring having 3 to 14 carbon atoms, including both single rings and polycyclic compounds in which one or several of the ring atoms is either oxygen, nitrogen or sulphur, such as furanyl, thiophenyl or imidazopyridine. Polycyclic rings are saturated, partially unsaturated or saturated.
Halogen(s) as used herein is selected from chlorine, fluorine, bromine or iodine.
The term “keto” is defined herein as a divalent oxygen atom double bonded to a carbon atom. Carbon atoms are present adjacent to the carbon atom to which the divalent oxygen is bonded.
When the compounds of formula (I) have at least one asymmetric carbon atom, they can exist in several stereochemical forms. The present invention includes the mixture of isomers as well as the individual stereoisomers. The present invention further includes geometrical isomers, rotational isomers, enantiomers, racemates and diastereomers.
Where applicable, the compounds of formula (I) may be used in neutral form, e.g. as a carboxylic acid, or in the form of a salt, preferably a pharmaceutically acceptable salt such as the sodium, potassium, ammonium, calcium or magnesium salt of the compound at issue.
The compounds of formula (I) are useful as positive allosteric GBR (GABAB receptor) modulators. A positive allosteric modulator of the GABAB receptor is defined as a compound which makes the GABAB receptor more sensitive to GABA and GABAB receptor agonists by binding to the GABAB receptor protein at a site different from that used by the endogenous ligand. The positive allosteric GBR modulator acts synergistically with an agonist and increases potency and/or intrinsic efficacy of the GABAB receptor agonist. It has also been shown that positive allosteric modulators acting at the GABAB receptor can produce an agonistic effect. Therefore, compounds of formula (I) can be effective as fall or partial agonists.
A further aspect of the invention is a compound of the formula (I) for use in therapy.
As a consequence of the GABAB receptor becoming more sensitive to GABAB receptor agonists upon the administration of a positive allosteric modulator, an increased inhibition of transient lower esophageal sphincter relaxations (TLESR) for a GABAB agonist is observed. Consequently, the present invention is directed to the use of a positive allosteric GABAB receptor modulator according to formula (I), optionally in combination with a GABAB receptor agonist, for the preparation of a medicament for the inhibition of transient lower esophageal sphincter relaxations (TLESRs).
A further aspect of the invention is the use of a compound of formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the prevention of reflux.
Still a further aspect of the invention is the use of a compound of formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment of gastroesophageal reflux disease (GERD).
Effective management of regurgitation in infants would be an important way of preventing, as well as curing lung disease due to aspiration of regurgitated gastric contents, and for managing failure to thrive, inter alia due to excessive loss of ingested nutrient. Thus, a further aspect of the invention is the use of a compound of formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment of lung disease.
Another aspect of the invention is the use of a compound of formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the management of failure to thrive.
Another aspect of the invention is the use of a compound of formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment or prevention of asthma, such as reflux-related asthma.
A further aspect of the invention is the use of a compound of formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment or prevention of laryngitis or chronic laryngitis.
A further aspect of the present invention is a method for the inhibition of transient lower esophageal sphincter relaxations (TLESRs), whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to subject in need of such inhibition.
Another aspect of the invention is a method for the prevention of reflux, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such prevention.
Still a further aspect of the invention is a method for the treatment of gastroesophageal reflux disease (GERD), whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
Another aspect of the present invention is a method for the treatment or prevention of regurgitation, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
Yet another aspect of the invention is a method for the treatment or prevention of regurgitation in infants, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
Still a further aspect of the invention is a method for the treatment, prevention or inhibition of lung disease, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment. The lung disease to be treated may inter alia be due to aspiration of regurgitated gastric contents.
Still a further aspect of the invention is a method for the management of failure to thrive, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
A further aspect of the invention is a method for the treatment or prevention of asthma, such as reflux-related asthma, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
A further aspect of the invention is a method for the treatment or prevention of laryngitis or chronic laryngitis, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
A further embodiment is the use of a compound of formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment of a functional gastrointestinal disorder (FGD). Another aspect of the invention is a method for the treatment of a functional gastrointestinal disorder, whereby an effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject suffering from said condition.
A further embodiment is the use of a compound of formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment of functional dyspepsia. Another aspect of the invention is a method for the treatment of functional dyspepsia, whereby an effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject suffering from said condition.
Functional dyspepsia refers to pain or discomfort centered in the upper abdomen. Discomfort may be characterized by or combined with upper abdominal fullness, early satiety, bloating or nausea. Etiologically, patients with functional dyspepsia can be divided into two groups:                1- Those with an identifiable pathophysiological or microbiologic abnormality of uncertain clinical relevance (e.g. Helicobacter pylori gastritis, histological duodenitis, gallstones, visceral hypersensitivity, gastroduodenal dysmotility)        2- Patients with no identifiable explanation for the symptoms.        
Functional dyspepsia can be diagnosed according to the following:
At least 12 weeks, which need not be consecutive within the preceding 12 months of                1- Persistent or recurrent dyspepsia (pain or discomfort centered in the upper abdomen) and        2- No evidence of organic disease (including at upper endoscopy) that is likely to explain the symptoms and        3- No evidence that dyspepsia is exclusively relieved by defecation or associated with the onset of a change in stool frequency or form.        
Functional dyspepsia can be divided into subsets based on distinctive symptom patterns, such as ulcer-like dyspepsia, dysmotility like dyspepsia and unspecified (non-specific) dyspepsia.
Currently existing therapy of functional dyspepsia is largely empirical and directed towards relief of prominent symptoms. The most commonly used therapies still include antidepressants.
A further aspect of the invention is the use of a compound according to formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment or prevention of irritable bowel syndrome (IBS), such as constipation predominant IBS, diarrhea predominant IBS or alternating bowel movement predominant IBS.
A further aspect of the invention is a method for the treatment or prevention of irritable bowel syndrome (IBS), whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
IBS is herein defined as a chronic functional disorder with specific symptoms that include continuous or recurrent abdominal pain and discomfort accompanied by altered bowel function, often with abdominal bloating and abdominal distension. It is generally divided into 3 subgroups according to the predominant bowel pattern:                1- diarrhea predominant        2- constipation predominant        3- alternating bowel movements.        
Abdominal pain or discomfort is the hallmark of IBS and is present in the three subgroups. IBS symptoms have been categorized according to the Rome criteria and subsequently modified to the Rome II criteria. This conformity in describing the symptoms of IBS has helped to achieve consensus in designing and evaluating IBS clinical studies.
The Rome II diagnostic criteria are:                1- Presence of abdominal pain or discomfort for at least 12 weeks (not necessarily consecutively) out of the preceding year        2- Two or more of the following symptoms:        a) Relief with defecation        b) Onset associated with change in stool frequency        c) Onset associated with change in stool consistency        
A further aspect of the invention is the use of a compound according to formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment or prevention CNS disorders, such as anxiety.
A further aspect of the invention is a method for the treatment or prevention of CNS disorders, such as anxiety, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
A further aspect of the invention is the use of a compound according to formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment or prevention of depression.
A further aspect of the invention is a method for the treatment or prevention of depression, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
A further aspect of the invention is the use of a compound according to formula (I), optionally in combination with a GABAB receptor agonist, for the manufacture of a medicament for the treatment or prevention of dependency, such as alcohol or nicotine dependency.
A further aspect of the invention is a method for the treatment or prevention of dependency, such as alcohol dependency, whereby a pharmaceutically and pharmacologically effective amount of a compound of formula (I), optionally in combination with a GABAB receptor agonist, is administered to a subject in need of such treatment.
For the purpose of this invention, the term “agonist” should be understood as including full agonists as well as partial agonists, whereby a “partial agonist” should be understood as a compound capable of partially, but not fully, activating GABAB receptors.
The wording “TLESR”, transient lower esophageal sphincter relaxations, is herein defined in accordance with Mittal, R. K, Holloway, R. H., Penagini, R., Blackshaw, L. A., Dent, J, 1995; Transient lower esophageal sphincter relaxation. Gastroenterology 109, pp. 601-610.
The wording “reflux” is defined as fluid from the stomach being able to pass into the esophagus, since the mechanical barrier is temporarily lost at such times.
The wording “GERD”, gastroesophageal reflux disease, is defined in accordance with van Heerwarden, M. A., Smout A. J. P. M., 2000; Diagnosis of reflux disease. Bailliére's Clin. Gastroenterol. 14, pp. 759-774.
Functional gastrointestinal disorders, such as functional dyspepsia, can be defined in accordance with Thompson W G, Longstreth G F, Drossman D A, Heaton K W, Irvine E J, Mueller-Lissner S A. C. Functional Bowel Disorders and Functional Abdominal Pain. In: Drossman D A, Talley N J, Thompson W G, Whitehead W E, Coraziarri E, eds. Rome I I: Functional Gastrointestinal Disorders: Diagnosis, Pathophysiology and Treatment. 2 ed. McLean, V A: Degnon Associates, Inc.; 2000:351-432 and Drossman D A, Corazziari E, Talley N J, Thompson W G and Whitehead W E. Rome I I: A multinational consensus document on Functional Gastrointestinal Disorders. Gut 45(Suppl. 2), II1-II81.9-1-1999.
Irritable bowel syndrome (IBS) can be defined in accordance with Thompson W G, Longstreth G F, Drossman D A, Heaton K W, Irvine E J, Mueller-Lissner S A. C. Functional Bowel Disorders and Functional Abdominal Pain. In: Drossman D A, Talley N J, Thompson W G, Whitehead W E, Coraziarri E, eds. Rome I I: Functional Gastrointestinal Disorders: Diagnosis, Pathophysiology and Treatment. 2 ed. McLean, V A: Degnon Associates, Inc.; 2000:351-432 and Drossman D A, Corazziari E, Talley N J, Thompson W G and Whitehead W E. Rome II: A multinational consensus document on Functional Gastrointestinal Disorders. Gut 45(Suppl. 2), II1-II81.9-1-1999.
A “combination” according to the invention may be present as a “fix combination” or as a “it of parts combination”.
A “fix combination” is defined as a combination wherein (i) a compound of formula (I); and (ii) a GABAB receptor agonist are present in one unit. One example of a “fix combination” is a pharmaceutical composition wherein (i) a compound of formula (I) and (ii) a GABAB receptor agonist are present in admixture. Another example of a “fix combination” is a pharmaceutical composition wherein (i) a compound of formula (I) and (ii) a GABAB receptor agonist; are present in one unit without being in admixture.
A “kit of parts combination” is defined as a combination wherein (i) a compound of formula (I) and (ii) a GABAB receptor agonist are present in more than one unit. One example of a “kit of parts combination” is a combination wherein (i) a compound of formula (I) and (ii) a GABAB receptor agonist are present separately. The components of is the “kit of parts combination” may be administered simultaneously, sequentially or separately, i.e. separately or together.
The term “positive allosteric modulator” is defined as a compound which makes a receptor more sensitive to receptor agonists by binding to the receptor protein at a site different from that used by the endogenous ligand.
The term “therapy” and the term “treatment” also include “prophylaxis” and/or prevention unless stated otherwise. The terms “therapeutic” and “therapeutically” should be construed accordingly.
Pharmaceutical Formulations
The compound of formula (I) can be formulated alone or in combination with a GABAB receptor agonist.
For clinical use, the compound of formula (I), optionally in combination with a GABAB receptor agonist, is in accordance with the present invention suitably formulated into pharmaceutical formulations for oral administration. Also rectal, parenteral or any other route of administration may be contemplated to the skilled man in the art of formulations. Thus, the compound of formula (I), optionally in combination with a GABAB receptor agonist, is formulated with a pharmaceutically and pharmacologically acceptable carrier or adjuvant. The carrier may be in the form of a solid, semi-solid or liquid diluent.
In the preparation of oral pharmaceutical formulations in accordance with the invention, the compound of formula (I), optionally in combination with a GABAB receptor agonist, to be formulated is mixed with solid, powdered ingredients such as lactose, saccharose, sorbitol, mannitol, starch, amylopectin, cellulose derivatives, gelatin, or another suitable ingredient, as well as with disintegrating agents and lubricating agents such as magnesium stearate, calcium stearate, sodium stearyl fumarate and polyethylene glycol waxes. The mixture is then processed into granules or compressed into tablets.
Soft gelatine capsules may be prepared with capsules containing a mixture of a compound of formula (I), optionally in combination with a GABAB receptor agonist, with vegetable oil, fat, or other suitable vehicle for soft gelatine capsules. Hard gelatine capsules may contain a compound of formula (I), optionally in combination with a GABAB receptor agonist, in combination with solid powdered ingredients such as lactose, saccharose, sorbitol, mannitol, potato starch, corn starch, amylopectin, cellulose derivatives or gelatine.
Dosage units for rectal administration may be prepared (i) in the form of suppositories which contain the active substance(s) mixed with a neutral fat base; (ii) in the form of a gelatine rectal capsule which contains a compound of formula (I), optionally in combination with a GABAB receptor agonist, in a mixture with a vegetable oil, paraffin oil, or other suitable vehicle for gelatine rectal capsules; (iii) in the form of a ready-made micro enema; or (iv) in the form of a dry micro enema formulation to be reconstituted in a suitable solvent just prior to administration.
Liquid preparations for oral administration may be prepared in the form of syrups or suspensions, e.g. solutions or suspensions, containing a compound of formula (I), optionally in combination with a GABAB receptor agonist, and the remainder of the formulation consisting of sugar or sugar alcohols, and a mixture of ethanol, water, glycerol, propylene glycol and polyethylene glycol. If desired, such liquid preparations may contain colouring agents, flavouring agents, saccharine and carboxymethyl cellulose or other thickening agents. Liquid preparations for oral administration may also be prepared in the form of a dry powder to be reconstituted with a suitable solvent prior to use.
Solutions for parenteral administration may be prepared as a solution of a compound of formula (I), optionally in combination with a GABAB receptor agonist, in a pharmaceutically acceptable solvent. These solutions may also contain stabilizing ingredients and/or buffering ingredients and are dispersed into unit doses in the form of ampoules or vials. Solutions for parenteral administration may also be prepared as a dry preparation to be reconstituted with a suitable solvent extemporaneously before use.
In one aspect of the present invention, a compound of formula (I), optionally in combination with a GABAB receptor agonist, may be administered once or twice daily, depending on the severity of the patient's condition. A typical daily dose of the compounds of formula (I) is from 0.1 to 100 mg per kg body weight of the subject to be treated, but this will depend on various factors such as the route of administration, the age and weight of the patient as well as of the severity of the patient's condition.
Methods of Preparation
The compounds according to formula (I) of the present invention, wherein Y=—NH—Z—R4 and wherein R1, R2, R1 and R4 are defined as above, Z is —SO2— or —C(S)—, may be prepared by the following general method (Scheme 1; related literature: Tetrahedron (1982), 38:1435-1441).
wherein aminoimidazoles (II) efficiently are converted into (Ia), using acyl chlorides, sulfonylchlorides, isocyanates or other electrophiles (typically 1.5-2.5 equivalents) in organic solvents such as THF or the like. The reaction is performed in the presence of polymer-supported diisopropylethylamine (PS-DIPEA; 1.5-3 equivalents) at ambient temperature to 50° C. with agitation over 4-18 hours. Filtration of the reaction mixture over the nucleophilic anion exchange resin Isolute-NH2, elution with THF and evaporation in vacuo yields the desired products as oils or amorphous solids.
When
the compounds according to formula (I) of the present invention may be prepared analogously to the synthesis described in Examples 1-2, i.e. following schemes 8 and 9.
The aminoimidazoles (II) are prepared from intermediates (III) or (IV) by heating the reagents under basic conditions with an alpha halo carbonyl compound (Scheme 2; literature: Tetrahedron Lett. (1966), 1885-1889 and Monatshefte für Chemie (1976), 107:1413-1421)

Intermediate (III) is prepared by substitution of the thiomethoxy group in intermediate (IV) by the R2 group according to Scheme 3.

Intermediate (IV) is prepared by treating dimethylcyanodithioimidocarbonate in ethanol with 1-2 equivalent of the primary amine and reflux for 3-5 hours (see Scheme 4). The reaction mixture is allowed to cool, evaporated in vacuo and then the desired compounds are either collected by filtration directly or subsequently after the product has precipitated out by the addition of water.

An alternative route to intermediate (II) is the treatment of intermediate (IV) with an alpha halo carbonyl compound in the presence of a base such as potassium carbonate providing intermediate (V). Subsequent treatment of intermediate (V) with nucleophiles such as e.g. alkoxy or thioalkoxy derivatives (e.g. NaOMe, NaOEt) provides intermediate (II) via thiomethyl group substitution and ring closure.
